Axonemal Dynein Visualized in Primary Cilia via Expansion Microscopy.

Primary cilia are essential sensory organelles whose structural complexity has challenged detailed imaging analysis. Ultrastructure expansion microscopy (U-ExM) offers a promising approach by physically enlarging specimens in hydrogels, enabling nanoscale protein mapping. Here, we apply U-ExM to pancreatic islet cilia and demonstrate the conserved presence of all four axonemal dynein subtypes, including prominent localization of the intermediate chain DNAI1 in both primary cilia and centrioles. These findings suggest that U-ExM is a robust tool for ciliary studies and provide evidence that primary cilia may possess motor capabilities that could reshape our understanding of their function.